1. Field of the Invention
The present invention relates to a golf club, such as an iron and a wood, and more particularly to an improvement in the hosel portion of a head of a golf club where a tip end of a shaft is connected.
2. Prior Art
In a golf club, as shown in FIG. 5, the tip end portion 10a of the shaft 10, which is substantially a tapered tube, is fastened in place by a bonding agent, etc. inside a shaft insertion hole 3 formed in the hosel portion 2 (called "hosel") of the head 1, thus connecting the head 1 to the shaft 10. One type of golf club, as seen from this FIG. 5, is provided with a tapered surface 4 on the inner circumferential surface of the opening end 3a of the shaft insertion hole 3 of the hosel 2. The tapered surface 4 opens outwardly and is chamfered at an angle .theta. of 20 to 45 degrees.
This tapered surface 4 is formed so as to alleviate the local concentration of stress in the shaft 10 which is derived from the impact at the time of hitting the ball, thus preventing breakage of the shaft.
However, this type of golf club has a problem. Though the tapered surface 4 is employed as a countermeasure against breakage of the shaft 10, it still cannot provide a sufficiently reliable anti-breakage effect, and damages to the club have occurred occasionally.